Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Separation of zirconium and uranium
4330509 Separation of zirconium and uranium
Patent Drawings:

Inventor: Henry
Date Issued: May 18, 1982
Application: 06/266,225
Filed: May 22, 1981
Inventors: Henry; Helen G. (Reno, NV)
Assignee: The United States of America as represented by the Secretary of the (Washington, DC)
Primary Examiner: Peters; G. O.
Assistant Examiner:
Attorney Or Agent: Brown; William S.Gardiner; Donald A.
U.S. Class: 423/11; 423/608; 423/85; 534/13; 556/55
Field Of Search: 423/11; 423/85; 423/608; 260/429.3; 562/585
International Class:
U.S Patent Documents: 1624162; 2967088; 2982600
Foreign Patent Documents:
Other References: "Chem. Abst.", vol. 44, 1950, p. 10600e..









Abstract: Zirconium is selectively precipitated from aqueous solutions containing zirconium and uranium by treatment with a precipitant consisting of tartaric acid or a tartrate.
Claim: I claim:

1. A method for separation and recovery of zirconium from a feed consisting of an aqueous solution of zirconium and uranium having a pH of about 0.2 to 1.0 comprising treatment of thesolution with a precipitant consisting of tartaric acid or a tartrate, the amount of said precipitant being sufficient to selectively precipitate zirconium as a tartrate with minimal precipitation of uranium.

2. The method of claim 1 in which the precipitant is tartaric acid.

3. The method of claim 1 in which the precipitant is ammonium tartrate.

4. The method of claim 1 in which the feed solution consists of a strip liquor from a solvent extraction process for recovery of zirconium from zircon sands.
Description: This invention relates toseparation and recovery of zirconium from aqueous solutions containing zirconium and uranium. Such solutions are typically those formed by the processes disclosed in U.S. Pat. Nos. 3,658,466 and 4,231,994. Those processes involve initial sulfuricacid leaching of zircon sands to extract zirconium, along with hafnium and uranium which are commonly present in the sands. Recovery of zirconium, with substantial separation from hafnium, is then accomplished by solvent extraction with an organicamine, followed by stripping with sodium chloride solution to remove the zirconium from the organic phase.

Separation of zirconium from uranium is, however, difficult since the uranium tends to accompany the zirconium in the solvent extraction and stripping steps. It is therefor desirable, and an object of the invention, to provide a simple andeconomical way of removing a major portion of the zirconium from the zirconium and uranium-containing strip solutions, with minimal removal of uranium. This is particularly desirable for production of nucleargrade zirconium, in which the uranium contentmust be reduced to 3 ppm or less in the final product.

It has now been found, according to the present invention, that such a removal of zirconium may be accomplished by means of a process involving precipitation of zirconium from such zirconium and uranium-containing feed solutions by means oftartaric acid or a tartrate. Tartaric acid or ammonium tartrate are the preferred precipitants, but other tartrates such as sodium tartrate may be used.

Precipitation of zirconium from the feed solution is accomplished by addition of precipitant in an amount, usually approximately stoichiometric, sufficient for maximum precipitation of zirconium, with minimal precipitation of uranium. When thefeed solution consists of a strip solution of the type discussed above, the amount of precipitant will usually range from about 0.05 to 0.3 mole. The precipitant is added with agitation, such as stirring, of the solution, and ambient conditions oftemperature and pressure are usually satisfactory. The pH of the feed is not critical, but will usually range from about 0.2 to 1.0. Addition of about 20 to 30 volume percent of methanol with, or following addition of, the precipitant is also usuallydesirable for the purpose of speeding settling and facilitating filtering of the flocculant precipitate.

Subsequent treatment of the zirconium tartrate precipitate will ordinarily consist of conversion to ZrO.sub.2 by conventional means such as roasting, with the ZrO.sub.2 ultimately being used as a feed material to make zirconium sponge.

The invention will be more specifically illustrated by the following examples.

EXAMPLE 1

A feed solution from a solvent extraction process for recovery of zirconium from zircon sands was treated according to the process of the invention. The feed consisted of a strip liquor obtained from use of a 1.5 molar NaCl strip solution tostrip zirconium from a zirconium-loaded amine extractant. The strip liquor contained 23 g/l zirconium, 12 ppm uranium relative to zirconium, 3.8 g/l chloride, 120 g/l sulfate, and was 0.44 normal with respect to hydrogen ion.

Ammonium tartrate in the amount of 10.6 grams was dissolved in 200 ml of the feed, and a 25 ml portion of methanol was added with stirring. A white precipitate was formed. After 20 minutes of standing, another 25 ml portion of methanol wasadded. After 45 minutes of additional stirring, the precipitate was permitted to settle for one and one-half hours, and the resulting amorphous precipitate was filtered, washed with two 25 ml portions of methanol and dried at 125.degree. C.

X-ray diffraction studies identified the major component of the precipitate as a zirconium tartrate compound containing approximately 27.5 to 27.7 percent zirconium. Eighty percent of the zirconium in the feed solution was thus recovered asprecipitate, and the dried precipitate contained 2.78 ppm uranium relative to zirconium.

EXAMPLE 2

A feed solution from a solvent extraction process for recovery of zirconium from zircon sands was treated according to the process of the invention. The feed consisted of a strip liquor obtained from use of a 1.5 molar NaCl strip solution tostrip zirconium from a zirconium-loaded amine extractant. The strip liquor contained 13 g/l zirconium, 10 ppm uranium relative to zirconium, 25 g/l chloride, 70 g/l sulfate, and was 0.20 normal with respect to hydrogen ion.

Tartaric acid in the amount of 2.58 grams was dissolved in 200 ml of the feed, and a 25 ml portion of methanol was added with stirring. A white precipitate was formed. After 20 minutes of standing, another 25 ml portion of methanol was added. The solution is stirred intermittently. After aging overnight, the resulting amorphous precipitate was filtered, washed with two 25 ml portions of methanol and dried at 125.degree. C.

X-ray diffraction studies identified the major component of the precipitate as a zirconium tartrate compound containing approximately 27.5 to 27.7 percent zirconium. Sixty-three percent of the zirconium in the feed solution was thus recovered asprecipitate, and the dried precipitate contained <1.9 ppm uranium relative to zirconium.

* * * * *
 
 
  Recently Added Patents
Information processing apparatus capable of authentication processing with improved user convenience, control program for information processing apparatus, and recording medium having control
Wiring structure in a semiconductor device, method of forming the wiring structure, semiconductor device including the wiring structure and method of manufacturing the semiconductor device
Method and apparatus for executing load distributed printing
Event handling in an integrated execution environment
Switched capacitor amplifier
System and method for confirming delivery of an electronic message
Method and system for filtering noises in an image scanned by charged particles
  Randomly Featured Patents
Sanitary napkin
Tamper-evident closure and method of making same
Identification and verification system
Guard for radial arm saw
Apparatus for removing bulk material from a dump
High strength-high conductivity Cu--Fe composites produced by powder compaction/mechanical reduction
Hose adapter and assembly incorporating the same
Information handling system including battery assembly having multiple separable subassemblies
Self-contained apparatus for the storage processing of blood
Liquid crystal display apparatus having adjustable viewing angle characteristics